Use a tape measure to measure the suitcase in inches.
Place the luggage on a flat surface and stand it upright. Measure the length or height of the luggage from the bottom to the top. Include any protruding areas, such as wheels and handles.
Determine the width of bag by measuring across its widest point.
Obtain the size of the suitcase's depth by measuring the area from the front to the back of the luggage. If measuring an empty suitcase, remember to take into account any pouches, pockets and extenders on the bag to get an accurate measurement.
Add the inches of the length, width and height together using a calculator or pencil and paper to determine the size of the suitcase.
